Cephalomannine, baccatin III, 10-deacetylbaccatin III, 10-deacetylpaclitaxel, 10-deacetylcephalomannine, 7-(1β-xyloxyl)-paclitaxel, 7-(1β-xyloxyl)-cephalomannine, 7-(1β-xyloxyl)-10-deacetylpaclitaxel and 7-(1β-xyloxyl)-10-deacetylcephalomannine and so on, in addition to the anticancer drug paclitaxel, can also be isolated from barks, leaves and roots of Taxus baccata plants by extraction. Some of said taxanes have certain anticancer activity, whereas some of them have no anticancer activity. However, they can be used for the preparation of paclitaxel or other taxanes (e.g., docetaxel) having high anticancer activities by the semi-synthetic method. There are not only many studies thereof, but also mature methods. In principle, there are three directions. One is to convert 7-(1β-xyloxyl)-taxanes; the second is to semi-synthesize paclitaxel by reacting side chains with paclitaxel parent nucleuses; and the third is to develop new nonnatural taxanes by reacting different side chains with paclitaxel parent nucleuses. Semilh, et al have cracked 7-(1β-xyloxyl)-using the enzyme method (see J. Nat. Prod., 1984, 47, 131). Zhang Hongjie has hydrolyzed 7-(1β-xyloxyl)-paclitaxel with aqueous HCl in the presence of the catalyst LX-97615 (see the application of CN1241565A). In addition, the method of oxidative cracking 7-(1β-xyloxyl)-using periodates was widely used (see the applications of U.S. Pat. No. 5,200,534A, U.S. Pat. No. 5,367,086A and U.S. Pat. No. 5,856,532A). Furthermore, there are a plurality of patents and theses regarding the reaction of side chains with paclitaxel parent nucleuses. However, said studies inevitably need to solve the contradiction between the acylation of C(10)-OH and the protection of 2′,7-OH. Currently, the general mode is to protect 2′,7-OH with a protecting agent selected from the group consisting of multimethyl silane, multiethyl silane, multimethyl-(ethyl)chlorsilane, and chloracetate (chloracetic anhydride), then to acylate C(10)-OH using an acylating agent such as acetic anhydride or chloracetyl, and finally to deprotecting the protecting groups of 2′,7-OH using a deprotecting agent such as thiourea. The typical method to solve the contradiction between the acylation and the protection is to use choroacetic acid (chloracetate) as a protecting agent, acetic anhydride as an acylating agent, thiourea as a deprotecting agent as disclosed in the application U.S. Pat. No. 5,200,534A. Nevertheless, the protective effects of said method are not quite satisfying, and about 11% 2′,7,10-triacetyl taxane will be produced, which reduces the yield of the products obtained by acylating C(10)-OH and finally reduces the yield of 10-acetyltaxane. Although the products of 2′,7-OH can be obtained by the hydrolysis of ester groups at C(2′)- and C(7)-positions using a weak alkali, it is very difficult to completely hydrolyze esters at C(7)-position without affecting C(10)-position esters. Further, during the acylation, the inert solvents used in the previous processes are hydrochloric ethers, ethers, molecular silicons, aliphatic ketones and tertiary amine compounds etc. What's used most is pyridine which has the best effects. However, the odor of pyridine really smells unpleasant. When pyridine is in an amount less than 1×10−6, there will have a strongly pungent odor. The maximum concentration acceptable in the air is 5×10−6, and there are strict requirements for the obturation of the preparation apparatus and the air circulation in the place of production.
There are many published research findings for full-synthetic taxanes, but they are not formally used in the industrial production yet. The procedures for the preparation of full-synthetic taxanes involve synthetizing paclitaxel parent nucleuses from some chemical intermediates by the reaction comprising many steps, and men introducing relevant side chains at C-13-position. Due to the activities of C(7)-OH and C(10)-OH or C(10)-OAc, it cannot do without the protection of C(7)-OH and the acylation of C(10)-OH during said reaction. The previous methods of protection and acylation are the same as those of semi-synthetic taxanes, and thus mere are the same problems in the preparation process of semi-synthetic taxanes. Accordingly, as for full-synthetic taxanes, it is also a problem to be further studied to solve the contradiction between the protection and the acylation.